1. Field of the Invention
This invention relates to a convenient copying apparatus which sufficiently functions both as a sheet original copying apparatus and a bulky original copying apparatus, and further accelerates the copying speed in response to the copy size, and in which additional convenient features are incorporated.
2. Description of the Prior Art
Heretofore, copying apparatuses used where classified into two types, that is, a copying apparatus for the exclusive use of sheet originals and another capable of copying three dimensional materials such as books and the like.
The copying apparatus for the exclusive use of sheet originals cannot copy bulky originals such as books and the like, but can obtain copies merely by introducing sheet originals in the insertion slot thereof, and since there requires no original board nor a return stroke of the optical system for the same process, it produces an accelerated copying speed (about twice).
Furthermore, since the organization of the apparatus is compact, the price of the apparatus is cheap. Furthermore, when the feed of sheet originals is manually carried out, it cannot catch up with the speed of the apparatus, in accordance with the use of the copying apparatus of higher speed, and therefore it is inefficient. While, from this aspect, it has been desired to provide an automatic original feeder (autofeeder), it is easy to provide a copying apparatus having an organization provided with such a device.
Although the apparatus capable of copying bulky materials such as books and the like has a great feature in that it can copy both sheet originals and books, it has such a structure that the copying operation is carried out by stretching the originals flatly on the original board. Hence, when sheet originals are desired to be copied, they cannot be copied unless they should be placed on the original glass by opening the original cover in the same manner as the case of copying bulky originals, and then closing the cover and pushing the copy button.
Moreover, since the presence of the return stroke of the original board or optical system causes time loss corresponding to that much, and hence the copying speed for the same process is necessarily lowered. Furthermore, the organization of the apparatus becomes more complicated and hence the price thereof becomes higher. It is also extremely difficult to make the apparatus provided with such a original autofeeder.
For the above described reasons, the copying apparatuses of the above described two types have their own market fields.
Then, in a mirror transfer type exposure device in which two groups of mirrors generally move at the speed rate of 2 : 1, as shown in FIG. 1, an illuminating section 101 once stops (starting point : a position shown by solid line in FIG. 1) by leaving a preliminary traveling area on this side of an available exposure area (zone of a original board 2), and begins to migrate from this position in a direction shown by arrow A. Further, in most cases, the stop station of the optical system after the completion of copying is coincident with the starting point thereof.
The above described preliminary traveling area is a zone indispensable for reducing to the utmost mechanical wear and fatigue (particularly deterioration of illuminating lamp) due to impact thereby to increase the durability of the device and obtaining an appropriate and excellent visible image, as an accelerating area for exposing the original at a preselected speed from the stop state or a shock absorbing area. That is, the vibration of mirror shade or the like generated by an abrupt speed variation must be erased completely before the exposure zone. Otherwise, it would appear as a synchronous vibration at the proximal end portion of the visible image, and hence good copying could not be effected.
Accordingly, in accordance with the increase in the scanning speed of the apparatus, this preliminary traveling area requires a considerable length and becomes more indispensable.
Under these conditions, in the device which has heretofore been contrived in copying sheet originals, the mirror system which had been positioned at said stop station has been shifted to any station within the range of the reciprocating motion by some means or other or the bulky original placing surface has been utilized as a sheet original exposure area by enlarging the same more than necessary up to the stop station of the optical system, thereby to transfer the sheet originals at a synchronizing speed to slit expose the same. However, in order to utilize a part of said bulky original placing surface and moreover, to transfer the sheet original, a complicated device using a belt or the like must be arranged, and the transfer becomes unstable, and, in copying the bulk originals, such a device must be avoided.
There has been proposed a system wherein by utilizing the fact that the illuminating section stops at a starting point spaced apart from the original board 2, a sheet original feeder is provided at the upper part of the stop station. According to this system, a system of feeding the original by holding the same between heretofore known ordinary rollers can be used, thus accurate transfer is carried out. Furthermore, an operation for transferring the illuminating section can be omitted and time can also be curtailed. However, since said stop station is not spaced so much from the original board 2, a bulky sheet original feeder generally becomes a hinderance in copying bulky originals. Particularly, in the case of copying bulky originals protruded out of the original board 2, such a device must also be avoided, and the organization and the operation of the apparatus become more complicated and troublesome.